1. Field of the Invention
This invention relates to a liquid-tight connector for connecting electrical wires together, and more particularly to a liquid-tight connector which is mounted in a through hole in a casing filled with a liquid, and connects electrical wires provided inside the casing and electrical wires provided outside the casing in a liquid-tight manner.
2. Prior Art
For example, in an automatic transmission of an automobile, electrical wires of a solenoid valve, various sensors and so on which are mounted inside a transmission casing so as to control the transmission device are connected to a control. unit provided outside the transmission casing, through a connector mounted in a through hole in the transmission casing.
However, the interior of the transmission casing is filled with oil for lubricating the transmission device. Therefore, the above connector must be designed to connect the electrical wires provided inside the transmission casing and electrical wires provided outside the transmission casing, in such a manner as to prevent the oil within the transmission casing from leaking to the exterior of this casing.
Therefore, there has heretofore been used a liquid-tight connector 1 as shown in FIGS. 5 and 6. This liquid-tight connector 1 comprises a housing 3 of a synthetic resin for mounting on a transmission casing (not shown). And a connector 5 of a synthetic resin has a male connector portion 13 for fitting in a female connector portion 7 of the housing 3.
The female connector portion 7 of the housing 3 includes an inner bottom wall 7a through which male metal terminals 9 extends, and a fitting peripheral wall 7c which extends from a peripheral edge portion of the inner bottom wall 7a in a direction of projecting of the metal terminals 9 and forms a fitting recess portion 7b into which the male connector portion 13 of the mating connector 5 can be fitted.
The connector 5 has female metal terminals 11 (for connection respectively to the metal terminals 9) received and held respectively in terminal receiving chambers formed in the male connector portion 13.
The other end portions (right end portions in FIG. 6) of the metal terminals 9, provided in the housing 3, extend through the inner bottom wall 7a of the female connector portion 7 into the interior of a transmission casing. And the other end portions are electrically connected respectively to connection terminals of electrical parts within the transmission casing.
The housing 3 is required to have a high sealing performance so that foreign matters will not intrude into the interior of the transmission casing and that working oil or the like within the transmission casing will not leak to the exterior.
Therefore, in the housing 3, usually, the metal terminals 9 are insert molded in the female connector portion 7 to be integrally connected thereto, and in that side (surface) of the fitting recess portion of the inner bottom wall 7a, a filling material-pouring recess 7d is formed around a base portions of metal terminals projecting from said inner bottom wall of said fitting recess portion. A suitable amount of a filling material 15, such as an epoxy resin, is poured into the filling material-pouring recess 7d, thereby perfectly sealing the metal terminal-passing portions of the female connector portion 7.
As shown in FIG. 8, the filling material 15 is poured into the filling material-pouring recess 7d in the housing 3 by the use of a nozzle 17 insertable into the fitting recess portion 7b. Generally, the fitting recess portion 7b in the housing 3 has a narrow open end, and therefore the nozzle 17 is inserted generally vertically into the fitting recess portion 7b, and then the filling material 15 is poured.
During the pouring of the filling material 15 by the nozzle 17, the filling amount is confirmed through the open end of the fitting recess portion 7b with the eyes, and when the liquid level of the poured filling material 15 reaches the vicinity of the upper edge of the filling material-pouring recess 7d, the pouring of the filling material is stopped.
However, in the above conventional housing 3, it is difficult to accurately confirm the displacement of the liquid level of the filling material 15 during the pouring of the filling material 15 by the nozzle 17, and there were possibilities that the filling amount was so small that the sufficient sealing performance could not be achieved and that the filling amount was so large that the filling material 15 overflowed into the fitting recess portion 7b.
In the case where the filling material-pouring recess 7d has a generally rectangular transverse cross-section as shown in FIG. 7, the filling material 15 poured into the filling material-pouring recess 7d vigorously flows along the vertical peripheral wall of the filling material-pouring recess 7d, and therefore the liquid level becomes slightly higher at corner portions X (where a surface tension of the filling material is higher than at the other portions) than at the other portions. Therefore, even if the amount of filling of the filling material 15 is proper, the liquid level projects an amount .DELTA.t beyond a pouring-limit line Z into the fitting. recess portion 7b at the corner portions X, as shown in FIG. 9.
The filling material 15, thus overflowed into the fitting recess portion 7b, is deposited on an inner surface of the fitting recess portion 7b, such as a bottom surface 7e thereof to be opposed to the front end surface of the male connector portion 13, and when this filling material 15 is solidified, there is a possibility that the two connectors are not properly fitted together.